Septic sewage-tank.



G. C. ANDREWS.

SEPTIC SEWAGE TANK.

APPLICATION FILED MAR. 20. I912. 1,204,534. Patented Nov. 14, 1916.

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G. C. ANDREWS.

SEPTIC SEWAGE TANK.

APPLICATION FILED MAR. 20. I912.

Patented NOV. 14, 1916.

3 S'HEETSSHEET 2.

G. C. ANDREWS.

Patented Nov. 14, 1916.

3 SHEETS-SHEET 3.

GEORGE C. ANDREWS, 0F MINNEAPOLIS, MINNESOTA.

SEPTIC SEWAGE-TANK.

Specification of Letters Patent.

Application filed March 20, 1912. Serial No. 685,120.

To all whom it may concern:

Be it known that I, GEORGE C. ANDREWS, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and. useful Improvements in Septic Sewage-Tanks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My present invention relates to septic sewer systems, and is particularly directed to the improvement of the septic tank structure, whereby better results and greater economy are obtained.

To the above ends, generally stated, the invention consists of the novel devices and combinations of devices hereinafter described and defined in the claims.

' In the accompanying drawings, which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings, Figures 1, 2 and 3 are views chiefly "in vertical section, but with some parts in full, showing difi'erent ways of connecting and locating the septic tank; Fig. 4 is a plan view of the septic tank; Fig. 5 is a vertical-section taken approximately on the line 90 m on Fig. 4, some parts being shown in full; and, Figs. 6 and are views in vertical section illustrating modified forms of the septic tank. y

I will first describe the preferred construction of the septic tank, shown in Figs. 1 to 5, inclusive. This tank is preferably constructed from sheet metal and is preferably made round or cylindrical, but may take other forms and may be of other materials. In the drawings, the numeral 1 indicates the said tank which is divided into two compartments, by a partition plate 2,

shown as extended diametrically thereof, and from top to bottom of said tank, and provided at its upper central portion with an overflow passage 3. The two compartments thus formed within the tank 1 may be appropriately designated, the one as the settling chamber 1, and the other as the siphon chamber 1 Located within the settling chamber 1 and extended downward from the top of the tank to a point considerably below the lower edge of the overflow passage 3 is a barrier plate or flange 4, the edges of which extend into close contact with the partition 2, so that no considerable flow of the liquid can take place at these points, but that, nevertheless, there may be leakage sufficient to allow the escape of air from the upper portion of the chamber 1 into the cham- Patented Nov. 14, 1916.

ber 1 This leakage is important because,

as will presently more fully appear, it permits, at certain times, both of the said chambers 1 and 1 to be completely filled with the sewer water. The important functions performed by the so-called barrier plate 4 will all be hereinafter fully noted. A comparatively small air vent pipe 5 is extended upward from the top of the siphon chamber 1*. The numeral 6 indicates removable covers which close clean-cut or inspection holes 7 The numeral 8 indicates drain plugs applied in the bottom of the tank 1 and normally closing drain passages which open from the bottoms of the two compartments of the tank. Opening into the upper portion of the settling chamber 1, through the top of the tank, is

an elbow 9, preferably a cast structure having an annular flange 10, bolted, or otherwise rigidly secured at the top of the tank,

and between which and the top of the tank a suitable gasket is applied to form a gas tight joint. This elbow 9 is shown as provided with a cleanout opening, normally closed by a plug 11. The siphon proper may take different forms, but, as shown, is made up of vertically extended pipe sections 12 and 13 and an elbow 14 which connects the upper ends thereof. The siphon elbow 14 is a U-shaped and preferably cast structure, intothe ends of which, the upper ends of the pipes 12 and 13 are preferably screwed. The end of the elbow 14 to which the upper end of the inner pipe 12 is attached, is provided with a projecting annular flange 15 that is bolted or otherwise rigidly secured to the top of the tank and between which, and the top of the tank, a suitable gasket is interposed to form a gas tight joint. The pipe 13 is located outside of the tank, while the pipe 12 is extended downward through the top of the tank and nearly, but not quite, to the bottom of the siphon chamber 1. The flange 15 on the elbow 14 serves as a simple and convenient means for accurately setting the siphon pipes 12 and 13 in trueyertical positions, assuming, of course, that the top of the tank 1 is set in a horizontal plane, which is the proper and intended arrangement,

In Figs. 1 and 2, the numeral 16 indicates the walls of a house or other building. In Fig. 1, the tank 1 is shown as located in the basement and supported by suitable legs 17. In this arrangement, the said tank is located as high up in the basement as practical, so as to obtain as great a fall as possible for the water discharged from the tank. In the construction illustrated in Figs. 1, 4 and 5, the numeral 18 indicates the sewage pipe which connects to the elbow 9. In the construction illustrated in Figs. 2 and 3, portions of the sewage pipe which connect to the said elbow 9 are indicated by the numeral characters 18 and 18". In all of the several arrangements of the tank, the numeral 19 indicates a sewage distributing pipe which leads from the lower outer end of the siphon, to-wit: from the pipe section 13 to the place of discharge which may be either above or below the surface of the ground. In Fig. 1, this distributing pipe 19 is shown as located entirely beneath the surface of the ground and is provided with branch distributing pipes 20. This arrangement of the distributing pipes, however, constitutes no part of the present invention.

In Fig. 2, the tank 1 is shown as located outside of the building, but above the surface of the ground, while in Fig. 3, the tank is shown as located outside of the building and below the surface of the ground. and is provided with a box-like cover 21. In Fig. 2, the vent pipe is indicated by the character 5, and in Fig. 3 said vent pipe is indicated by the character 5'.

The tank illustrated in Fig. 6 is like that illustrated in Figs. 1 to 5, inclusive, exceptthat the partition for dividing the tank into two compartments is not employed. In Fig. 7, the so-called settling chamber is within a tank: 21, and the siphon chamber is within a similar tank 22, the said two tanks being connected at their upper portions by an overflow conduit or passage 23. In this arrangement a barrier plate 4 is employed, a sewage pipe 9*18 opens into the tank 21, and a vent pipe 5 and a siphon 12--13"1t leads from the tank 22. The tank shown in Fig. 6 has a single compartment, but for some uses will serve the purpose. The double tank arrangement shown in Fig. 7, however, has a settling chamber and siphon chamber, and the action of this tank is very similar to that of the curved form of the tank shown in Figs. 1 to 5, inclusive. Hence, the description of the operation of the said tank shown in Figs 1 to 5, inclusive, best shown in detail in Figs. 4 and 5, will serve the purpose of this case. The sewer water will first accumulate in the so-called settling chamber 1, at the level of the lower edge of the overflow passage 3, and will not fall below this level, (see Fig. 5), wherein the liquid level is inknown that there are highl dicated by the character a. When the sewer water rises higher than the level 2, it will overflow through the passage 3 into the siphon chamber l and after the level in the latter chamber has been raised to the level 2, the level of the Water in both chambers will rise to the top of the tank. When the said two compartments of the tank are filled with the sewer water, and there is a rush of sewer water into the chamber 1, such as is produced by ordinary discharges from a closet tank, the impact produced will have an action very analogous tothat of a hydraulic ram, and the water will be caused to spurt or suddenly flow upward through the siphon, and thereby start the said siphon into action. When the siphon is thus started into action, it will continue to drain water from the tank until it has completely drained the siphon chamber 1 and lowered the water in the settling chamber 1 to the normal level .2. Before the siphon action will be started, both chambers of the tank will be filled with water so that the impact from the intermittent flow or flush of water from the sewer pipe or stack 18 will start the siphon. If the first flush or delivery of water into the tank, after the tank has been filled, is such as to produce but a very slight impact, the water may sometimes rise a short distance into the vent pipe 5 and into the elbow 14 of the siphon, but sooner or later, there will be a flush of water suflicient to start the siphon action. Obviously, the higher the water rises into the elbow 14, the less is the impact required to start the siphon.

In septic tanks of this character, it is well im ortant decompositions which take p ace in the settling chamber due to the action of certain bacteria. Thus bacteria accumulation chiefly at the surface of the water is in what would usually be designated as scum on the surface of the water and it is, therefore, important that such bacteria be not entirely washed out of the settling chamber. This is just what is accomplished by the application of the so-called barrier plate 4, already described.

In all of the several forms of the septic tank, there is a siphon for intermittently draining the tank (to-wit, at leastone compartment thereof) of the accumulated sewage water. In all instances, the tank has a substantially closed top (except possibly for a. small air ventingpipe), and the discharging siphon has its crown extended above the top of the tank. These features are of the very greatest im rtance, because in this tank structure, an impact produced by a flushing of sewage water is relied upon to intermittently start the siphon into action. Hence, before the siphon can be started by such impact, it is m: that discharg', siphon the tank be first filled with water, so that 'the impact delivered to the confined water within the tank will produce the sudden rise 3' water in the siphon necessary to carry the same over the crown of the siphon, and thereby start the siphon action by a sort of a hydraulic ram action.

What I claim is:

1. A septic tank having a settling chamber and asiphon chamber connected at their upper portions by an overflow passage, and provided with rigid substantially closed tops, said settling chamber having an inlet conduit, and said siphon chamber having a arranged to intermittently discharge therefrom, the diameter of the inlet conduit being materially larger than the diameter of the siphon.

2. In a sewage system, a settling chamber and a siphon chamber connected at their upper portions by an overflow passage, and provided with substantially closed tops approximately on the same level, said settling chamber having an inlet conduit, and said siphon chamber having a discharge siphon, the crown of which extends above the tops of the said two chambm substantially as described, the diameter or said inlet conduit being materially larger than the diameter of said siphon.

3. A septic tank having a partition with an overflow passage, said partition dividing said tank into a settling chamber and into a siphon chamber, a'sewage pipe delivering into said settling chamber, a slphon leading from said siphon chamber, and a barrier plate extending downward from the top of said tank into said settling chamber and having its ends extending loosely against said partition, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

GEORGE C. ANDREWS. Witnesses:

HARRY D. KILGoRE, F. D. MERCHANT. 

